If you've had a few drinks, it's never a smart idea to reach for your keys. Even if you're sure that you're fine, check to see what the Keychain Breathalyzer says. In under 20 seconds, you can find out if your BAC (Blood Alcohol Content) exceeds the legal limit in your state.

To test BAC, hold down the test button for 10 seconds, exhale into the Keychain Breathalyzer, and then check the LED readout. Three levels can be displayed: less than .03 BAC, .03-.05 BAC, and greater than .05 BAC.

The Keychain Breathalyzer runs on 2 AAA batteries and comes in handy even if you're not checking your blood alcohol content level. It also has a built-in LED flashlight and clock with a timer.